Operational Schedule Flexibility and Infrastructure Investment: Capacity Trade-Off on Single-Track Railways

2016 ◽  
Vol 2546 (1) ◽  
pp. 1-8 ◽  
Author(s):  
C. Tyler Dick ◽  
Darkhan Mussanov
Keyword(s):  
Infrastructure Investment ◽  
Single Track ◽  
Trade Off ◽  
Schedule Flexibility ◽  
Investment Capacity ◽  
Operational Schedule

Improving Railway Operational Efficiency with Moving Blocks, Train Fleeting, and Alternative Single-Track Configurations

2020 ◽  
Vol 2674 (2) ◽  
pp. 146-157 ◽  
Author(s):  
Adrian Diaz de Rivera ◽  
C. Tyler Dick ◽  
Leonel E. Evans
Keyword(s):  
Heterogeneous Traffic ◽  
Capital Investments ◽  
Single Track ◽  
Delay Performance ◽  
Train Control ◽  
Schedule Flexibility ◽  
Financial Consequences ◽  
Operating Strategies ◽  
Traffic Composition ◽  
Double Track

With installation of positive train control (PTC) on many U.S. rail corridors, Class I railroads may soon leverage these investments in communications network infrastructure to implement “advanced PTC” systems incorporating moving blocks. Train control with moving blocks can benefit operating strategies that dispatch fleets of multiple trains running at minimum headways. On single-track corridors with passing sidings long enough to hold multiple trains, fleeting may increase the efficiency of train meets, reduce train delay, and yield incremental capacity benefits. Alternative single-track configurations with fleet-length sidings at double the spacing of conventional single-train sidings can facilitate these operating strategies while minimizing additional track infrastructure and associated capital and maintenance costs. To investigate the operational synergies between moving blocks, fleeting, and longer but less frequent sidings, Rail Traffic Controller software is used to simulate and compare the delay performance of train operations on representative rail corridors for different combinations of fleeting strategy, train control system, siding configuration, and freight traffic composition. Operating fleets in conjunction with moving blocks produces the lowest overall train delay in specific cases of low schedule flexibility and heterogeneous traffic. With more efficient meets, moving blocks and/or fleeting primarily benefit low priority trains that typically wait for opposing traffic during train meets. Such incremental line capacity benefits have short-term financial consequences as they allow additional capital investments in double track to be deferred. Knowledge of train delay performance under moving blocks and fleeting will aid railway practitioners evaluating investments in advanced PTC systems and track infrastructure expansion.

scholarly journals Infrastructure investment under uncertainty

2010 ◽  
Vol 6 (4) ◽  
Author(s):  
Lewis Evans
Keyword(s):  
Natural Disasters ◽  
Wide Spectrum ◽  
Investment Decisions ◽  
Infrastructure Investment ◽  
Small Probability ◽  
Investment Under Uncertainty ◽  
Trade Off ◽  
Probability Of Occurrence ◽  
Ex Post ◽  
Physical Infrastructure

Many volatile factors influence the performance of infrastructure and these yield a range of uncertainties when forward-looking investment decisions are being considered. This article is restricted to consideration of physical infrastructure, which has a wide spectrum of such factors. It includes physical events such as earthquakes that are beyond the influence of humankind, other events for each of which there is a very small probability of occurrence, and events that will almost certainly occur at some point within any reasonable period of time. It also includes economic events relating to uncommon financial episodes and common, but uncertain, volatility in demand and cost. Rare physical events have implications for investment in infrastructure that provides some mitigation of the effects of these events. In so doing, there is a trade-off between providing in advance for remotely likely but substantial events in specific, and usually costly, redundancy infrastructure, and having an economy with the resources to deal ex post with natural disasters. Obviously, some intermediate position will be socially desirable. 

A Flow-Preserving Algorithm for the Time-Cost Trade-Off Problem

1982 ◽  
Vol 14 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Suleyman Tufekci
Keyword(s):  
Time Cost ◽  
Trade Off

Dual Goals for Speed and Accuracy on the Same Performance Task

2012 ◽  
Vol 11 (3) ◽  
pp. 118-126 ◽  
Author(s):  
Olive Emil Wetter ◽  
Jürgen Wegge ◽  
Klaus Jonas ◽  
Klaus-Helmut Schmidt
Keyword(s):  
Memory Scanning ◽  
Performance Task ◽  
Performance Tasks ◽  
Trade Off ◽  
Test Experiment ◽  
Trade Offs ◽  
New Finding ◽  
Sternberg Paradigm ◽  
Speed Accuracy ◽  
Speed And Accuracy

In most work contexts, several performance goals coexist, and conflicts between them and trade-offs can occur. Our paper is the first to contrast a dual goal for speed and accuracy with a single goal for speed on the same task. The Sternberg paradigm (Experiment 1, n = 57) and the d2 test (Experiment 2, n = 19) were used as performance tasks. Speed measures and errors revealed in both experiments that dual as well as single goals increase performance by enhancing memory scanning. However, the single speed goal triggered a speed-accuracy trade-off, favoring speed over accuracy, whereas this was not the case with the dual goal. In difficult trials, dual goals slowed down scanning processes again so that errors could be prevented. This new finding is particularly relevant for security domains, where both aspects have to be managed simultaneously.

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